Agitator

ABSTRACT

The present disclosure is directed to an agitating apparatus comprising an agitating blade assembly, said agitating blade assembly including upper and lower disk means which are spaced apart by a plurality of radially disposed plate means, said lower disk means also containing a plurality of radially disposed blade plate means attached to its bottom side, and agitating shaft means extending through an opening in the upper disk means and attached to the top side of the lower disk means.

United States atent Tanaka, deceased et al.

[54] AGITATOR [72] Inventors: Masatami Tamika, deceased, late of Machida-shi, Tokyo, Japan by ltsuko Tanaka, administratrix; Tadashi Hirotani, Tokyo, Japan [73] Assignee: Kyowa Hakko-Kogyo Co., Ltd.,

Tokyo, Japan [22] Filed: March 4, 1969 [21] Appl. No.: 804,743

[52] US. Cl. ..259l96, 259/1 1 l, 261/84, 416/184 [51] Int. Cl. ..'...B0lf 5/16 [58] Field of Search ..259/111, 102, 96, 95; 416/182, 416/184, 185, 186; 261/84, 93, 32;

[56] References Cited 9 9 UNITED STATES PATENTS 473,530 4/1892 Smith ..259l96 1,413,724 4/1922 Groch ..259l96 1,084,210 1/1914 Howard ..259/107 1,571,735 2/1926 Queisser ..416/185 1,919,970 7/1933 Woods ..416/184 1451 Sept. 12, 1972 2,230,146 Myers ..259/9 3,284,055 11/1966 Johansen ..259l96 X 3,298,444 l/l967 Haas ....4l6/l 86 3,362,338 H1968 Stethern ..416/183 3,387,832 6/1968 Nelson ..261/93 FOREIGN PATENTS OR APPLICATIONS 1,474,582 2/ 1967 France ..259l96 552,573 4/1943 Great Britain ..259/96 Primary ExamineF-Walter A. Scheel Assistant Examiner-Alan I. Cantor Attorney-Craig and Antonelli [57] ABSTRACT The present disclosure is directed to an agitating apparatus comprising an agitating blade assembly, said agitating blade assembly including upper and lower disk means which are spaced apart by a plurality of radially disposed plate means, said lower disk means also containing a plurality of radially disposed blade plate means attached to its bottom side, and agitating shaft means extending through an opening in the upper disk means and attached to the top side of the lower disk means.

12 Claims, 4 Drawing Figures PATENTEDSEPIZIQTZ 3.690.621

SHEET 1 [IF 2 'm hi.

INVENTOIB I'M-91mm 1711mm 19MB 77900: MamM ATTORNEYS PMENTEDSEP 12 I972 sum 2 0F 2' 3.690.621

INVENTORS ATTORNEYJS The present invention relates to an improved agitating apparatus for promoting gas-liquid contact reaction. More particularly, the present invention is directed to an improved aeration-agitatingapparatus comprising disk means provided with a plurality of plate means which cooperate to promotea gas-liquid contact reaction.

A gas-liquid reaction apparatus wherein gas is blown into a liquid phase, or an apparatus usedfor the submerged culturing of aerobic microorganisms, such'as an agitating blade assembly, a turbine having 4 to 6 flat blades, a turbine having curved blades, a disk turbine having bottom blades, and the like, is well known. In

' these type of apparatus, a gas is blown from the bottom side of said apparatus by means of nozzles or a sparger and the gas bubbles produced thereby are made finer and dispersed by a blade assembly. However, it has been found that these flat blade or curved blade turbines .possess many disadvantages including a very large power consumption which is necessary for obtaining a thorough contact of the gas-liquid phase and for obtaining a high rate of gas dissolution.

Although the disk turbine having bottom blades can give a large shearing force to the gas-liquid mixture, and although a high rate of gas dissolution can be obtained with a relatively low power consumption, only a small amount of liquid is discharged by the blade assembly and thus uniform agitation cannot be obtained in the tank. Accordingly, the resulting insufficient mixing makes the yield of reaction product lower. a

Generally, an agitating blade assembly for an aeration agitating tank must obtain a high rate of gas dissolution with a corresponding low power consumption and a shortenedmixing time while obtaining uniformity or'evenness throughout the entire tank. Accordingly, it isdesired to provide a blade assembly which will give a high shearing effect to gas bubbles while utilizing as small a power consumption as possible, thereby making said bubbles finer and dispersing them uniformly throughout the entire reaction vessel in a short period of time. Advantageously, the blade assembly should discharge as much as is necessary to establish uniformity throughout the entire reaction vessel and improve the circulating flow in said vessel.

An object of the present invention is to avoid the prior art disadvantages in the agitation of gas-liquid mixtures.

Another object of the present invention is to provide an improved agitating apparatus for promoting gasliquid contact reactions.

A further object of the present invention is to provide an improved agitating apparatus which utilizes a low power consumption, exhibits uniform agitation in a shorter mixing time and produces an improved yield of reaction product.

A still further object of the present invention is to provide an improved agitating apparatus which gives a high shearing effect to gas bubbles thereby making said bubbles finer and disperses said bubbles uniformly throughout the entire reaction mixture.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and bles with as littlea power-consumption as possible, and v specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modification within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Pursuant to the present invention, it has been found that the above-mentioned disadvantages may be eliminated and a much improved agitating apparatus for promoting gas-liquid contact reactions may be obtained by providing a blade assembly for the agitating apparatus that gives a high shearing effect to gas bubby utilizing said shearing effect to make finer gas hobbles and disperse said bubbles'uniformly throughout the entire reaction mixture.

The present invention will become more fully un- Y derstood from the detailed description give hereinbelow and the accompanying drawings which are given not limitative of paratus of the present invention;

FIG. 2 is a side view of the agitating blade assembly of the present invention;

FIG. 3 is a top view of the disposition of the curved plates disposed between the upper and lower disk means; and r FIG. 4 is a bottom view of the disposition of the blade plates attached to the bottomof the lowerdisk means.

Referring now to the drawings wherein like reference numerals are .used throughout the various views to designate like parts, the apparatus of the present invention comprises a flat disk 1 provided with a top cover 2, said elements being spaced apart by a plurality of radially extending curved plates 3. The diskmeans 1 also contains a plurality ofradially extending blade plates 4 attached to its bottom side. An agitating shaft 6 extends through an opening in the top cover 2 and is attached to the top side of the flat disk 1 by means of a boss 7.

The flat plates 1 and blade plates 4 are usually called a disk turbine having bottom blades, and are generally used in aeration agitating tanks. A high rate of gas dissolution can be obtained with a small unit power requirement by utilizing the blade assembly according to the present invention. By providing curved blades 3, a large discharging amount can be achieved with very little power consumption, and the mixing time can be shortened. By rotating said agitating blade assembly for aeration agitation, the liquid above the agitating blade assembly is drawn in through a clearance between the top cover 2 and the rotating shaft 6 and discharged by the curved blades 3. Bubbles produced by a gas discharged from nozzles or a sparger provided below the agitating blade assembly are made finer and dispersed vby the blade plates 4 and mixed with the liquid discharged by the curved plates 3, and distributed uniformly throughout the entire reaction mixture, whereby the entire reaction mixture of the reaction vessel can be controlled to a uniform dissolved gas concentration.

The blade plates 4 as referred to herein can be flat plates, corrugated plates, curved plates, or the like, depending upon the property of the liquid being agitated.

An agitating blade assembly using flat blade plates 4, as shown in FIGS. 1, 2, 3 and 4, was employed in a 4-H TABLE 1 Mixing time Number of revolution 200 r.p.m. 300 r.p.m.

Identification of blade assembly Agitating blade assembly for aeration agitation of the sec. [4 sec. present invention Turbine with 6 flat blades 29 sec. 21 sec; Turbine with bottom blades 34 sec. sec.

TABLE 2 Consumed power Number of revolution 200 r.p.m. 300 r.p.m.

Identification of blade assembly Agitating blade assembly for aeration agitation of the 5.] H.P 17.0 H.P. present invention Turbine with 6 flat blades 7.l H.P. 24.4 H.P. Turbine with bottom blades 3.9 HP. 13.0 HP.

Table 1 shows the situation where 2.3 kl of water was charged into a tank. 900 l per minute of air was introduced into the water and agitation was conducted at 200 r.p.m. and 300 r.p.m., respectively. A pH meter of the immersion type was placed in the tank and while a caustic soda solution was added to the top of said tank, the time required for the pH to become constant was measured. As can be readily noted, the mixing time for the same number of revolutions is shorter when using the agitating blade assembly of the present invention when compared to the flat blade turbines and the bottom-blade disk turbines of the prior art. Table 2 shows the power required for agitation when 900 l per minute of air was introduced into the tank and measured by a strain gage.

According to Tables 1 and 2, a mixing time of 20 seconds can be obtained with 5.] HF. when using the agitating main assembly of the present invention,

whereas when using a flat blade turbine and a bottomblade disk turbine, mixing times could not be reduced to 20 seconds, even when using 24 HP. and 13 H.P., respectively.

Table 3 shows the results of a measurement of the sodium sulfite oxidation rate obtained by operations similar to that shown in Tables 1 and 2.

the present invention Turbine with 6 flat blades Turbine with bottom blades The sodium sulfite oxidation rate is lower but power consumption is higher when using the flat blade turbine rather than the agitating blade assembly of the present invention, when compared at the respective r.p.m. For example, only 0.570 kgmol/m hr.atm. is obtained with a power consumption of 13.0 HR in the case of the bottom-blade disk turbine, and thus the power efficiency is not as good as the agitating blade assembly of the present invention.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be apparent to one skilled in the art are intended to be included within the scope of the follow ing claims.

What is claimed is:

1. An agitating apparatus comprising an agitating blade assembly, said agitating blade assembly including upper and lower flat horizontal circular disk means which are parallel to one another and which are spaced apart by a plurality of radially extending curved plate means, said upper disk means being provided with a centrally disposed opening, a plurality of radially extending flat blade plate means attached to the bottom side of the lower disk means, the fiat blade plate means having horizontal bottom edges which are parallel to said lower disk means, and agitating shaft means extending through the centrally disposed opening and secured to the top side of the lower disk means.

2. An agitating apparatus comprising an agitating blade assembly, said agitating blade assembly including upper and lower circular disk means which are spaced apart by a plurality of radially extending curved plate means, said upper disk means being provided with a centrally disposed opening, a plurality of radially extending flat blade plate means attached to the bottom side of the lower disk means and agitating shaft means extending through the centrally disposed opening and secured to the top side of the lower disk means, wherein the curved plate means extend into the centrally disposed opening.

3. The apparatus of claim 2, wherein the curved plate means are tapered to a point extending from the periphery of the opening into said opening.

4. The apparatus of claim 2, wherein the curved plate means extend from the periphery of the disc means into the centrally disposed opening.

5. The apparatus of claim 2, wherein the flat blade plate means extend inwardly from the periphery of the lower disk means to a position spaced from the center of said disk means.

6. An aeration-agitating apparatus comprising a plurality of radially extending flat blade means attached to the underside of a lower flat horizontal circular disk means, said flat blade means having lower horizontal edges which are parallel to said lower disk'means, a plurality of substantially radially extending curved blade means attached at their bottoms to the upper side of said lower disk means, an upper flat horizontal circular disk means attached at the bottom side thereof to the tops of said curved blade means, and connecting means for connecting at least one of said disk means t rotating means.

7. An apparatus according to claim 6, characterized in that said upper disk means is provided with a centrally disposed opening and in that said connecting through the centrally disposed opening and attached to the upper side of said lower disk means.

8. An apparatus according to claim 7, characterized in that said agitating shaft means is attached to the upper side of said lower disk means by way of an annular cylindrical boss, said boss being integral with said lower disk means.

9. An apparatus according to claim 6, characterized in that said upper disk means is substantially smooth over the entire surface of the upper side thereof up to the edges of said opening, said opening being formed as a bore through said upper disk means, the edges of said bore intersecting with the surface of the upper side of said upper disk means such that said bore is open to the surrounding medium in all directions above said upper disk means.

10. An apparatus according to claim 6, characterized in that both said flat blade means and said curved blade means includes an agitating shaft means extending means extend substantially perpendicularly with respect to the surfaces of the respective disk means.

11. An aeration-agitating apparatus comprising a plurality of radially extending flat blade means attached to the underside of a lower circular disk means, a plurality of substantially radially extending curved blade means attached at their bottoms to the upper side of said lower-disk means, an upper circular 'disk means attached at the bottom side thereof to the tops of said curved blade means, and connecting means for connecting at least one of said disk means to rotating means, said upper disk means being provided with a centrally disposed circular opening, each of said curved blade means tapering downwardly from the edge of said upper disk means which delimits the opening to respective points located on the lower disk means radially inwardly from said edge.

12. An apparatus according to claim 1, characterized in that said opening is formed as a bore through said upper disk means, the edges of said bore intersecting with the flat upper surface of said upper disk means such that said bore is open to the surrounding medium in all directions above said upper disk means. 

1. An agitating apparatus comprising an agitating blade assembly, said agitating blade assembly including upper and lower flat horizontal circular disk means which are parallel to one another and which are spaced apart by a plurality of radially extending curved plate means, said upper disk means being provided with a centrally disposed opening, a plurality of radially extending flat blade plate means attached to the bottom side of the lower disk means, the flat blade plate means having horizontal bottom edges which are parallel to said lower disk means, and agitating shaft means extending through the centrally disposed opening and secured to the top side of the lower disk means.
 2. An agitating apparatus comprising an agitating blade assembly, said agitating blade assembly including upper and lower circular disk means which are spaced apart by a plurality of radially extending curved plate means, said upper disk means being provided with a centrally disposed opening, a plurality of radially extending flat blade plate means attached to the bottom side of the lower disk means and agitating shaft means extending through the centrally disposed opening and secured to the top side of the lower disk means, wherein the curved plate means extend into the centrally disposed opening.
 3. The apparatus of claim 2, wherein the curved plate means are tapered to a point extending from the periphery of the opening into said opening.
 4. The apparatus of claim 2, wherein the curved plate means extend from the periphery of the disc means into the centrally disposed opening.
 5. The apparatus of claim 2, wherein the flat blade plate means extend inwardly from the periphery of the lower disk means to a position spaced from the center of said disk means.
 6. An aeration-agitating apparatus comprising a plurality of radially extending flat blade means attached to the underside of a lower flat horizontal circular disk means, said flat blade means having lower horizontal edges which are parallel to said lower disk means, a plurality of substantially radially extending curved blade means attached at their bottoms to the upper side of said lower disk means, an upper flat horizontal circular disk means attached at the bottom side thereof to the tops of said curved blade means, and connecting means for connecting at least one of said disk means to rotating means.
 7. An apparatus according to claim 6, characterized in that said upper disk means is provided with a centrally disposed opening and in that said connecting means includes an agitating shaft means extending through the centrally disposed opening and attached to the upper side of said lower disk means.
 8. An apparatus according to claim 7, characterized in that said agitating shaft means is attached to the upper side of said lower disk means by way of an annular cylindrical boss, said boss being integral with said lower disk means.
 9. An apparatus according to claim 6, characterized in that said upper disk means is substantially smooth over the entire surface of the upper side thereof up to the edges of said opening, said opening being formed as a bore through said upper disk means, the edges of said bore intersecting with the surface of the upper side of said upper disk means such that said bore is open to the surrounding medium in all directions above said upper disk means.
 10. An apparatus according to claim 6, characterized in that both said flat blade means and said curved blade means extend substantially perpendicularly with respect to the surfaces of the respective disk means.
 11. An aeration-agitating apparatus comprising a plurality of radially extending flat blade means attached to the underside of a lower circular disk means, a plurality of substantially radially extending curved blade means attached at their bottoms to the upper side of said lower disk means, an upper circular disk means attached at the bottom side thereof to the tops of said curved blade means, and connecting means for connecting at Least one of said disk means to rotating means, said upper disk means being provided with a centrally disposed circular opening, each of said curved blade means tapering downwardly from the edge of said upper disk means which delimits the opening to respective points located on the lower disk means radially inwardly from said edge.
 12. An apparatus according to claim 1, characterized in that said opening is formed as a bore through said upper disk means, the edges of said bore intersecting with the flat upper surface of said upper disk means such that said bore is open to the surrounding medium in all directions above said upper disk means. 